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Challenges in sports cardiology and pre-participation screening

Sports related cardiovascular (CV) events are always dramatic. A cardiovascular pre-participation screening (PPS) has been recommended by the Sports Cardiology Section of the European Cardiovascular Association for Prevention and Rehabilitation of the ESC. Athletes’ hearts are associated with electrical, structural and functional adaptations. However, there is currently a very important question, namely what is normal and what is not normal concerning the athlete’s heart? Four main questions concerning this topic were presented in this scientific session.

Dr Domenico Corrado from Padua, Italy, presented the electrical repolarisation change limits in young athletes. It is well known that in about 45-50% of high-level training athletes (≥8 h/week), mainly endurance athletes, some ECG changes can be observed. Most of them, such as bradycardia, low grade atrio-ventricular block, incomplete right bundle branch block (IRBB) are benign. However, in less than 5% the ECG abnormalities can mimic or hide potential lethal cardiac diseases. This concerns mainly the repolarisation. Observation of negative T waves in an athlete in ECG leads other than L3, Vr and V1 is suspicious and requires CV exams and at least echocardiography, exercise test and cardiac MRI if needed. Indeed, negative T wave in leads L1-Vl, L2-L3-Vf and or V5-V6 is a very sensitive sign (96% in athletes) of hypertrophic cardiomyopathy (HCM). Negative T waves in right leads other than V1 are a very sensitive sign (88% in athletes) of arrhythmogenic right ventricular disease (ARVC). In case an athlete is asymptomatic with no familial history of sudden death, if the CV check-up is totally normal, competitive sport must be authorized. However, in all cases, an annual CV follow-up is required.

Juvenile T wave pattern can also raise questions. It must be noted that the prevalence of negative T waves on right ECG leads in young athletes is not different than in an age-matched sedentary population. Negative T waves in other leads than V1 are observed in 4.1% (2.3% V1-V2 and 1.8% V1-V3) of athletes before 16 years old. It is more frequent before 14. The prevalence of ARVD in this population was 0.1%.

Early Repolarisation

An early repolarisation (ER) pattern is very frequent in athletes. It concerns mainly the right ECG leads (V2-V3). Sometimes questions arise with Brugada syndrome, particularly when it is associated with an IRBB. Brugada syndrome concerns mainly the phase 1 of the repolarisation and benign ER concerns phases 2 and/or 3. Thus it is important to calculate the STJ/ ST80 ratio, which must be >1. In case of a marked J point elevation and a STJ/ST80 ratio <1, Brugada syndrome must be eliminated. 
Dr Alessandro Biffi from Rome, Italy, raised another important question concerning asymptomatic ventricular extrasystoles in athletes: are they benign or potentially fatal?
Ventricular arrhythmias (VA) are a frequent cause (30% in Italy) of ineligibility for the practise of intense sports in athletes. The disqualification is associated with a decrease of the CV risk in case of complex VA. However, VA are not always malign. Classical ECG criteria of “benign” and “malign” arrhythmias must be of course specified. In all cases, a CV exam is necessary (echocardiography, exercise test and if needed Holter recording with a training session, high amplification ECG, cardiac MRI and electrophysiology study). Three questions are important: is the athlete asymptomatic and without sudden death in the family, does VA complexity significantly increase during exercise test, and does the heart look “healthy”. In case of one yes answer, the athlete is in most cases ineligible for competition. However, a full detraining period of 3 months may be proposed. Disappearance of VA is a positive sign, and in the speaker’s experience, VA does not reappear after re-training. The athlete’s heart does not seem to be arrhythmogenic per se, but it is possible that the autonomic balance disturbances (sympathetic > parasympathetic) induced by some training periods and mainly during tapering may favour VA in some athletes. 

Importance of Ethnicity

Actually, most of the limitations proposed concern Caucasian athletes. However, the rising number of black athletes is very important. Moreover, most data concern American football, which is a very specific sport and concerns players with a very big body surface area. Lastly, sports-related sudden death often concerns black athletes. Dr Sanjay Sharma from London, GB, presented the results of studies concerning black elite athletes (BA). Data concerning male and female athletes came from a cooperative study between his group and the group of Dr F Carré (Rennes, France). Concerning male BA, echocardiography analysis showed that the left ventricle (LV) is dilated as in white athletes (WA), but wall parietal thickness (WPT) is significantly increased (11.3 ± 1.7, 8-16 mm vs 10.1 ± 1.5, 7-14 mm) and that in 18 and 3% WT exceeds respectively 13 and 15 mm. The same results are observed in all sport disciplines studied. In all cases of WPT>15 mm, LV hypertrophy was symmetric and cardiovascular exams (exercise test, Holter, cardiac MRI) as follow-up were normal.

Concerning ECG, LV hypertrophy (56 vs 42 %), ST segment elevation (86 vs 73 %), diphasic (u-shaped ST segment elevation followed by a negative part of the ending T wave, 34 vs 6 %) and deep inverted T waves (16 vs 2 %) are more frequent in BA than in WA. Concerning inverted T waves, they must disappear after a detraining period and they are very rare in leads V5-V6. No pathologic Q waves, no left BBB and no ST segment depression >1mm were observed in BA. Concerning female BA, WPT was significantly increased in BA in comparison with WA and 3% of BA presents a WPT >11m vs 0% in WA. These results are not correlated with the sports discipline. Concerning the ECG, negative T waves concern mainly V1-V4 and were observed in 14% of BA vs 2% in WA. Lastly echocardiographic data collected in adolescent athletes confirms the higher prevalence of parietal hypertrophy in BA, WPT >12 mm in 8% of vs 1% in WA.

Role of Right Ventricle

Concerning the athlete’s heart, most of the studies have focused on the LV. However, most of us have forgotten that old physiology studies have shown that during physical exercise the work developed by the right ventricle (RV) is proportionally higher than that of the LV. Dr Andre La Gerche from Leuven, Belgium, underlined the importance of the evaluation of the RV in highly trained young athletes. Three questions were developed: what is normal in terms of RV adaptations, can we distinguish the normal from the pathological, and can prolonged exercise contribute to RV remodelling. The place of exercise echocardiography is very important to study RV in athletes. In accordance with the scarce literature, which concerns mainly endurance athletes, echocardiography and cardiac MRI, it seems that the RV/LV ratio is higher in athletes than in sedentary people. The end diastolic RV volume seems to be similar, but the end systolic RV volume seems to be higher in athletes, thus the resting RV ejection fraction appears lower in athletes than in the sedentary population (50.5% vs 57.6%).

Finally, one strain rate study reveals a reduction rate of myocardial deformation in elite athletes with RV dilatation. Some studies have described in some symptomatic endurance athletes potential lethal VA coming from the right ventricle. The physiology of the arrhythmogenic substrate is not clearly understood and the part played by potential doping cannot be totally excluded, even if it does not seem to be the main factor. Electrophysiology studies, and more rarely myocardial biopsies, may be needed in order to distinguish physiologic from pathologic. From a physiological point of view, during intense exercise it is clear that the end systolic wall stress (ESWS = P x r/2h) observed in the RV is higher than in the LV. This is especially true in athletes. For example, pulmonary artery pressure during maximal exercise is 61 ± 13 mmHg in athletes and 47 ± 6 mmHg in untrained subjects. Concerning, the ESWS its increase in athletes is of 170% and 23% in respectively RV and LV vs 83 and 14% in sedentary people.

After an ultra endurance exercise (>10 hours) a transient but significant decrease of RV function was observed. It is associated in 27% of athletes with a transient abnormal wall motion. These alterations are both significantly correlated with the increase of troponin I and BNP. Thus, it is possible that ultra endurance exercise has deleterious effects on RV function in some athletes. However, further studies are needed to confirm this hypothesis.

Take-Home Messages

Thus the take home messages of this session are:

  1. Negative T waves are uncommon in athletes and must be considered as a warning signal. A CV examination and follow up are always needed.
  2. VA, even if complex, in athletes always requires CV examination. In asymptomatic athletes without heart disease, a full detraining period is recommended. In case of significant improvement of the VA, intensive sport participation must be authorized, but with the education of the athlete and with an annual CV follow-up.
  3. Adapted heart limits must be analysed in accordance with the sporting discipline, the age, the gender and also with the ethnicity. Indeed, in BA, male, female or adolescent, marked repolarisation disturbances with negative T waves from V1 to V4 are more frequent than in WA. But, negative T waves in V5-6 are always suspicious. BA develop more marked parietal hypertrophy and the upper limits proposed in this population are 16 mm in males and 14 mm in females.
  4. We must think about the RV in athletes, mainly endurance athletes. RV in athletes must be studied by echocardiography and cardiac MRI in case of any doubt. During exercise, the hardest work is performed by the RV. It seems that a long history of prolonged intense exercise can induce RV remodelling in some subjects with potential injury and possible malign arrhythmias.




Challenges in sports cardiology and pre-participation screening

The content of this article reflects the personal opinion of the author/s and is not necessarily the official position of the European Society of Cardiology.